The invention concerns devices for detecting partial discharge in insulation system of rotating electrical machines with low capacitance decoupling.
Pre-installed partial discharge couplers on high-voltage stator windings of rotating electrical machines in the form of generators and motors are known. Measuring the pulse amplitude is realized at the base of each coupler. They are designed for high frequency measurement of partial discharge in the frequency range above 40 MHz. The couplers have a strong high pass effect so that measurement and as a result thereof local depth of the measurement is limited.